Brake mechanism



April 16, 1929. H. PIEPER BRAKE MEGHANI SM Filed Janf, 1928 4 Sheets-Sheet L V2M/for.'

April` 16, 1929. H. PIEPER 1,709,150

BRAKE MECHANISM Filed Jan. 6, 1928 4 Sheets-Sheet 2 April 16, 1929. H. PIEPER BRAKE MECHANISM 4 Sheets-Sheet Filed Jan. 6, 1928 |H m um u ro, 0,1 c e w .9 m 4. llwl) al 22:22am? 1 n n m m um m /&\w V/ April 16, 1929. H. PIEPER BRAKE MECHANISM 4` ySheets-Sheet Filed Jan. 6, 1928 Patented '.Apr. 16, 19,29.

PATENT orf-lcsb HEN'BI PIETER, 0F BRUSSELS, BELGIUM.

rma MECHANISML" Application med January 6, 1928, Serial No.

The resent invention relates to a motive device or working a brake in which the brake levers are connected `to a piston movable in a cylinder into which liquid is first forced by two drivingpistons, and afterwards by one of them, the other'forcing liquid into a reser voir.

According to the invention, the communication between this reservoir and a cylindrical space or chamber wherein thel second piston works is governed by a valve gear controlled bythe movement of the drivmg pistons.

The movement of these pistons may be caused for 4instance -by the influence of the /variations in pressure which it causes in the spaces or ducts included in the device.

The present invention concerns especially the case in which to act-nate the above specified valve gear use is made of the variations of pressure which will occur on the side of the piston attached to the brake levers.

The variations of pressure may act directly or by the intermediary-of an electric circuit, or even by pneumatic or hydraulic means etc.

The drawings attached to the present speciication represent some-examples of diferent constructions according to the invention.

Fig. 1 is a vertical sectional view of an arrangement in which the valve gear-includes two valves.

Fig. 2 is a similar view of a modiicatin in which the valve gear includes one valve only.

Fig. 3 is a sectional view of a further modiication in which the valve gearincludes two valves, `011e of which is controlled by an electric circuit. Fig. 4 shows a modification of Fig. 3 in which the valve gear includes one valve only.

vThe'piston 57 connected to the brake gear represented diagrammatically by a lever 1 fitted with a block arranged to come into contact with .a wheelis' movable in a cylinder 57'L communicating by 'means of a duct 57". with a cylinder 18I in which the driving piston 18 is movable, afterwards referred to as the first driving piston; In this piston an opening closed byva valve 12. Thi pening` 18F' lrovides communicationbetw n the cylind 18k and a cylindrical space or chamber 9 in which works the second driving piston 13.

To obtain the braking action,

a return sprino 15k.

18m lis arrangedA capable of being 244,934, andin .Belgium January 1e, 1927.

pistons 13 and 18 are moved in the direction of the arrow Xby suitable means, mechanical, hydraulic, pneumatic or electric. During the :[irstphase, the liquid displaced by the two pistons passes by the duct 57b into the brake cylinder 57 After a certain length of stroke of the driving pistons, the Valve 12 is caused to close on its seating 12k. .This valve 12 is carried by a rod 12 of which one end enters the piston ,13 where it is subjected to the action of a spring 12m tendin to cause a collar 12b fitted at the other end o said rod 12 to abut against a member 12n carried by the frame of the apparatus and projecting into the cylinder 18k.

At the beginning of the stroke of the piston 13 in the direction of the arrow X the valve 12 remains stationary while the spring 12m expands progressively. v

As long as the liquid compressed in the space or chamber 9 by the movement of the second driving piston 13 does not find any other outlet, the valve 12 remains lifted o its seatin so as to allow this li uid to move towards t e cylinders 18k and 5 a.

When, owing yto the application of the brake-bldcks against the wheels, the pressure rises in these cylinders, the valve 12 will close on to its Iseating 12k. This increased pressure also acts on the side of the piston 15a facing the cylinder 18k and will displace, said piston, thereby opening the valve 15 which is connected to it and which is interposed between. the reservoir 14 and the space 9. j

It will be noticedrthat the side ofthepiston '15 facing the space 9 is'subjected to the pressure existing in this space and tends to balance the action of th'is pressure on the valve 15. Said valve 15,- which openstowards the reservoir 14, is subjected to theaction of y The opening of the valve 15, comblned with the closing of the valve 12, initiates a second braking phase during which the piston 18 alone forces liquid into the cylinder 57;.the resistance opposed to the motion of the second driving piston 13 fbeing insignificant, owing to the valve 15 being open.

From the moment when the driving pistons 13 and 18 have assumed a position such that the valve 12-is capable of closing on its seating 12k, the spindle of the valve 16, openin towards the space or chamber 9, is released rom the driving its resilient support 13m, -which normally 110 liquid inthe reservoir 14 to return tothe space 9.

At the moment when the valve 12 leaves its seating, an acceleration takes place in the.

movement of the piston 57, owing to the fact that the two pistons 13 and 18 aspire liquid simultaneously.

If the piston 57 does not follow this move- Y ment, the pressure is lowered in the space or chamber 9 and the valve 16 tends to open. To avoid this disadvantage the valve 16 is forced on to its seating at the moment when the valve 12 itself lis forced open by the action of the abutment 12 against the collar 12b fixed 4on the -rod 12, From this moment, the liq- -uid is exhausted from the cylinder 57a -by the combined action of the two drivin pistons 13 and 18, without,y allowing any iquid to pass from the reservoir14 into the space'9.

If the play between the blocks and the wheels has increased, this increase will be compensated by the liquid which passes through the opening 18m from the moment when the valve 12 is capable 0f closing it.

When the brakes are released, the quantity of liquid which will pass the opening of the by a pi valve 16 corresponds to the quantity of liquidwhich will have passed the o ening 18' to compensate the play which ha been produced.

If on the other hand the play diminishes,

. the pressure will rise inthe cylinder 18 owing to the application of the brake-blocks against the wheels before the valve 12 is enabled to return to its seating. This increase of pressure will cause the valve 15 to open, and will allow the excess liquid to return to the reservoir 14.

In thelcase of Fig. 2, lthe functions of the valves 15 and 16 are fulfilled by a single valve 15', opening towards the space 9. This valve is constantly induced to return to its seating by a return spring 16k. It can be lifted from said seating either by a fall in pressure occurring in the space 9, or by a sitive thrust of a. plston 15 subjected to t e pressure in the cylinder 18k which is transmitted to it 18. The spring 15, which has a certain-lnitial tension, opposes the movement of the piston 15a that tends to open the valve 15.

When the brakes are applied the valve 15 will be positively lifted from its seating when the pressure in the cylinder 18k' will have in" the creased suicicntly to compress the spring 15 and eventually the resilient'support13. lVhen the brakes are released, the Valve 15 can be lowered from its -seating by the fall of pressure which may occur in the space 9. It is automatically returned to its seating by the support 13' as soon as the valve 12 itself is positively-opened. ,c

The working is therefore similar to that of the device represented in Fig. 1.

In the case of Fig. 3, the valve gear, except for a few constructional details,'is similar t0 that of Fig. 1, the same members serving the same purposes in the two cases.

The valvev 12 is fixed on a rod 12, one end of which enters the piston 13 while the other end is threaded and fitted with a nut and locknut 12q arranged to rest against the frame.

The valve 12 is subjected to the action of a spring 12D arranged on the rod 12a between the valve and the in ide frame-wall and tends to draw the n andlock-nut against theframe.

.The piston 13 consists of a bottom 13 and a sleeve 13". This sleeve, in which on the vside next to the valve 16, an opening 13 is provided, fulfills the same function as the spring -13.n and the carrier13k of Fig. 1.

As soon as the pistons 13 and 18 have moved far enough inward or downward to close the valve 12 on its seating 12k, the part 13t of sleeve 13b which normally maintains the valve 16 closed, passes beyond anduncovers the port 16 of said valve and puts it into communication with the reservoir 9, by means of the opening 13 arranged ,in the sleeve.

Consequently when the brakes are released,

the valve 16 cannot open during theperiod when the valve 12 is positively li seating.

v `The. pressure in the duct 57b causes, by means of an electric circuit, the valve 15 to open; such circuit having included in it a source -of current 15", electro-magnet 15n and switch 15P-15.

ed from its The increased pressure in the duct 57 b actsl on the flexible diaphragm 15f, kept in its normal position by a balanced spring 15v acting on a rod fixed to the diaphragm. The switch lever 15l .-isfitted ,with a finger which strikes the contact lfvand closes the electric circuit, 'thereby energizing magnet 15n and attracting its armature 15m, with the result that valve 15 is opened, and the space or chamber 9 and the reservoir 14 are placed in communication.

In the case of Fig 4,'the action of the I according to the position of the lever 15w for' applying)the brakes at S or for releasing them at During the period when the brakes are breaks the electric circuit lu-s-t-nd-c. During this same period the switch v15G-J5" alone will actuate the electro-ma et and in the same way as inthe prece ing case (Figc). .p

During the period when the brakes are released, the lever 15W, which is then in con-v tact with the block 15, closes the circuit 158-15-11/-f1i-cZ-c which shunts the switch lever 151. A

This latter will not function again during the period when the brakes are released` (the pressure having fallen in the duct 57") but the current will flow through the controlling lever 15",' .contacts 15u and 15t, strip 15", spring 15d, electro-magnet 15.

The strip 15 is fixed on the sleeve 13b of the piston 13 and makes contact with a spring 15d. These twoy members are in series with the electro-magnet and the sourcel of current, so that the current will only be interruptedA in the electro-magnet 15 when the strip 15- has left the spring 15d.

This breaking of the circuit will cause the positive closure ofthe valve 15 on its seating; this closing taking place at the moment when the valve 12 opens.

. The`r control lever 15"` can beoperalted directly by'hand, or by means of a pedal; and.

it is also possible, without departing from the scope of the invention, to place thls lever under the control of the brake-controlling device or of a part of the brake rodding by means of, for example, a member secured to said device or to said part which-will' follow themovement thereof in thepdirection corresponding to brake setting or releasing. What I claim is: l 1. A motive device for brakes, consisting of brake levers connected to a pistonv movable in a cylinder into which liquid is injected first by two driving pistons and afterwards by one of them, the second piston then forcin the liquid ,vinto a reservoir, a plurality o communications between the reservoir and a space wherein the second piston works, and a valve gear controlling said communications and itself controlledvby the displacement of the driving pistons.

2. A motive device for brakes, consisting of brake levers connected to a piston movable in a brake cylin er into which liquid is injected first by two driving pistons and afterwards by one of them, the second piston then forcing the liquid ,into a reservoir, a communication between the reservoir and a space wherein the second piston works, and a valve controlling said communication and itself controlled by the variations in pressure in the brake cylinder.

3. A. motive device for brakes, consisting of brake levers connected to a iston movable i in a brake cylinder into whi liquid is injected first by two driving pistons and afterwards by one of them, the second piston then forcing the l1qu1d into a reservoir, a communication between thereservoir and a space wherein the second piston works, and a valve controlling said communication and fixed to a movable member, said valve being subjected at one side to the pressure in the brake cylinder and at the other side to the pressure in the aforesaid space.

4. kA motive device for brakes consisting of brake levers connected to a piston movable in a brake cylinder into which liquid is injected "irst by two driving pistons and afterwards by one of them, the second piston then forcing the liquid into a reservoir, and a valve controlling communication between -the brake cylinder and a space wherein the second piston works, said valve acting to cut off all communication between the reservoir and the `aforesa1d space as soon as sald valve leaves its'seating at the end of the return stroke of the driving pistons. y

5.A motive device'for brakes consisting of brake levers connected to a piston movable in a cylinder into which liquid is injected first by two driving pistons and afterwards by one of them, the second piston then forcing the liquid into a reservoir, a communication between the reservoir anda space wherein the second piston works, a valve to control said" electromagnet, and a, switch to control the' activity of said magnet actuated by a movable member. subjected to the pressure 1n the brake cylinder.

K 7. A motive device for. brakes, consisting of brake levers connected to a piston movable in a fbrake lcylinder into which liquid is injected first by two. driving pistons and afterwards by one of them, the second piston then forcing the liquid intoareservor, a com-4 munication between the, reservoir and a space wherein the second piston works, a valve to control said communication actuated by an electro-magnetga switch to'controlthe activity of said magnet actuatedby a'movable member subjected tothe pressure in thebrake.

cylinder, and .a lever for putting the said switchin parallel during the timen of releasing the brakes. l i

In testimony whereof I affixA my` signature.

vIncluir PIEPER. 

